JPH03281434A - Cap for fuel tank - Google Patents

Abstract

PURPOSE:To release gas accumulated in a fuel tank before removing a cap from a filler neck by shifting a plunger at the return position resisting against the elastic force of a spring, and by releasing the pressure in the fuel tank to the atmosphere by opening a pressure valve. CONSTITUTION:When a plunger 50 is manually pushed resisting against the elastic force of a spring 56 before removing a cap for a fuel tank from a filler neck when oil is filled, a pressure valve mechanism 60 opens. As a result, the gas generated in the fuel tank can be released to the atmosphere.

Description

[Detailed description of the invention] W-anus production! - The present invention relates to a cap, particularly a fuel tank cap attached to a fuel filler port of an automobile.

Generally, the filler neck that forms the fuel filler port of a car's fuel tank is installed so as to be exposed outside the car body. When refueling, the filler cap is removed from the filler neck. From the viewpoint of ease of operation and airtightness, a structure in which the filler cap is attached to the filler neck by tightening or loosening the filler cap onto an internal thread provided on the filler neck is often adopted.

By the way, high-pressure gas is generated in the fuel tank due to evaporation of fuel. For example, the vaporization phenomenon occurs when the remaining amount of fuel in the fuel tank decreases, when the fuel tank becomes hot due to the heat generated by the engine or the rise in outside air temperature as the car is driven, or when driving at high altitudes with low atmospheric pressure. This becomes noticeable and a large amount of fuel vaporizes inside the fuel tank.

When the filler cap is removed from the filler neck for refueling when the pressure in the fuel tank has increased, a large amount of fuel gas may blow out from the fuel filler opening of the fuel tank.

In order to avoid the fuel gas blowout phenomenon, for example,
No. 3-33267 discloses a pressure relief fuel cap.

When this fuel cap is rotated in the removal direction,
A passageway is formed that communicates the fuel tank with the atmosphere. When the internal pressure of the fuel tank is high, gas can be vented from the fuel tank by rotating the filler cap in the removal direction.

With conventional fuel caps, cap installation requires a torque regulating device that acts when the cap is installed, and a rotation regulating device that temporarily stops the relative rotation of the plunger when moving the valve gear to the open position when the cap is removed. equipment is provided. Both of these torque regulating devices and rotation regulating devices are implemented by springs made of resin. Springs molded from such resin have the disadvantage that the elastic modulus varies greatly with changes in temperature. That is, in a high temperature environment, the elastic modulus of the spring decreases, so when removing the fuel cap.

The fuel cap may be removed from the filler neck before the passage formed in the fuel cap is opened to a predetermined cross-sectional area. In this case, since fuel gas blows out after the fuel cap is removed, a sufficient fuel gas leakage effect cannot be obtained with the fuel cap attached.

Conversely, the elastic modulus of the spring increases in a low-temperature environment, so
When removing the fuel cap, strong manual force is required to simultaneously operate the torque regulating device and the rotation regulating device. Therefore, removal of the fuel cap requires rotation. In order to solve the above problem, it is impossible to determine at the time of design the material and shape of the spring that always provides a predetermined elastic modulus even under temperature changes.

An object of the present invention is to provide a fuel tank cap that can reliably release the fuel gas accumulated in the fuel tank.

The fuel tank cap according to the present invention has one end formed with an open end, the other end formed with a vent leading into the fuel tank, and a locking part that locks onto the filler neck of the fuel tank. a case having an outer periphery, a housing fixed within the case and having an opening that communicates with the inside of the fuel tank through a vent in the case, and a cover that is rotatably attached to the open end of the case and covers the case and the housing. and a torque adjustment mechanism that disconnects the operational connection between the case and the cover when the rotation torque generated when the cover is rotated in the direction of tightening the case into the filler neck exceeds a predetermined value, and a torque adjustment mechanism that disconnects the operational connection between the case and the cover when the rotational torque generated when the cover is rotated in the direction of tightening the case into the filler neck exceeds a predetermined level. The fuel tank is equipped with a pressure valve mechanism that opens the fuel tank and releases the pressure inside the fuel tank to the atmosphere when the fuel tank is opened.

This fuel tank cap is provided with a plunger attached to the cover so as to be movable between an outer return position and an inner operating position, and a spring that presses the plunger outward. By moving the plunger from the return position to the operating position against the elasticity of the spring, the pressure valve mechanism is opened and the pressure within the fuel tank is released to the atmosphere.

The pressure valve mechanism includes a positive pressure valve that communicates the pressure in the fuel tank to the atmosphere when the pressure in the fuel tank exceeds a predetermined positive pressure level, and a plunger that moves to an actuated position or when the pressure in the fuel tank exceeds a predetermined positive pressure level. and a negative pressure valve that releases the pressure within the fuel tank to the atmosphere when a predetermined negative pressure level is exceeded. Also.

A latching mechanism is provided to retain the plunger in the actuated position. When the plunger is in the actuated position, the latch mechanism engages a portion of the torque adjustment mechanism, and when the torque adjustment mechanism is actuated, the latch mechanism is unlocked and the plunger is returned to the return position.

The negative pressure valve and the positive pressure valve are arranged so as to be in contact with each other, and when the negative pressure valve and the positive pressure valve are relatively separated, the pressure in the fuel tank is communicated with the atmosphere.

■-If the plunger is manually pushed in before removing the fuel tank cap from the filler neck during refueling, the pressure valve mechanism opens, allowing the gas generated in the fuel tank to be released to the atmosphere.

The pressure valve mechanism that works with the plunger is #! When the pressure of the gas generated in the fuel tank is below a predetermined level, the negative pressure valve is activated. Therefore, the pressure within the fuel tank is released to the atmosphere through the intake passage.

Further, when the pressure of the generated gas exceeds a predetermined level, the positive pressure valve is activated and the gas is released to the atmosphere through the exhaust passage.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a fuel tank cap according to the present invention will be described below with reference to FIGS. 1 to 6.

As shown in FIGS. 1 to 3, the fuel tank cap consists of a metal case 1 which is provided with a screw 11 on the outer periphery as a locking portion that locks into a filler neck (not shown) of the vehicle body.
has 0. A resin housing 20 is fixed inside the case 10. Further, the open end 12 of the case 10
A cover 30, which is attached and detached during refueling, is attached so as to be non-removable and rotatable. The upper parts of the case 10 and the housing 20 are covered by a cover 30. cover 3
A torque adjustment mechanism 40 for adjusting the tightening torque for the filler neck is provided inside the filler neck.

A handle 32 is provided in the center of the cover 30, and the handle 32 is provided with a hole 32a in which one end 50a of the plunger 50 is slidably disposed, and the - end 50a is movable along the central axis of the cover 30. In the illustrated example, the upper surface 51 of the plunger 50 is biased by a spring 56 toward a return position flush with the outer surface of the handle 32.

Next, the metal case 10 constituting the outer shell is screwed onto the filler neck of the fuel tank using a screw 11 provided on the outer periphery. Further, the open end 12 of the case 10 is fixed to the annular open end 21 of the housing 20 by caulking. A vent hole 14 communicating into the fuel tank is provided at the bottom 13 of the case 10.

An annular open end 21 is formed in the housing 20 fixed inside the case 10, and on the upper surface of the annular open end 21,
A number of latches 22 are provided radially. The cross-sectional shape of the latch 22 is as shown in FIGS.
It has a vertical surface 22a that is substantially perpendicular to the main surface of 0, and an inclined surface 22b that is inclined at a predetermined angle. The latch 22 constitutes a part of the torque adjustment mechanism 40. Further, the bottom 23 of the housing 20 is provided with an opening 24 that communicates with the interior of the fuel tank through the vent 14 of the case 10. A shoulder portion 25 and an undercut holding portion 26 are provided at the upper portion of the bottom portion 23. Also.

A pressure valve mechanism 60 is installed inside the housing 20 to release the pressure inside the fuel tank to the atmosphere when the pressure inside the fuel tank reaches a predetermined positive pressure level or negative pressure level.

A plastic cover 3 is attached to the open end 12 of the case 10.
0 is rotatably mounted. The peripheral edge 31 of the cover 30 is fitted into the open end 12 of the case 10 by an undercut from the outside, and the cover 30 is attached to the open end 12 of the case 10 so as not to fall off.

A torque adjustment mechanism 40 is provided between the cover 30 and the housing 20 to keep the tightening torque of the screw 11 of the case 10 to the filler neck constant and suitable at all times.

The torque adjustment mechanism 40 is known as shown in Japanese Patent Laid-Open No. 50-103856.

Generally speaking, the elastic claws 33 are integrally or separately molded inside the cover 30, and the elastic claws 33 are engaged with and released from the latches 22 of the housing 20 as the cover 30 rotates.For example, the elastic claws 33 are used to tighten the cover 30. When rotated in the direction, the elastic claw 33
comes into contact with the inclined tooth surface 22b of the latch 22, and the case 10
The outer peripheral screw 11 is screwed into the filler port of the filler neck.

When the tightening torque due to the rotation of the cover 30 exceeds a predetermined level, the elastic pawl 33 overcomes the inclined tooth surface 22b and the cover 30 rotates idly, preventing the case 10 from being screwed into the filler neck with a larger tightening force. is prevented.

Conversely, if the cover 30 is rotated in the removal direction.

The elastic pawl 33 abuts against the vertical tooth surface 22a of the latch 22, and the full rotational torque of the cover 30 is transmitted to the case 10, allowing the fuel tank cap to be easily removed from the filler neck.

As shown in FIG. 1, the plunger 50 is biased by a spring 59 toward a return position where the top surface 51 is flush with the handle 32 of the cover 30. When the plunger 50 is pushed in as shown in FIG. 2, the latch mechanism 70 holds the plunger 50 in the actuated position. The plunger 50 is provided with a flange 52 having a locking member 71 arranged to be retractable from the outer peripheral surface. The inner end of the locking member 71 is disposed within the hole 52a of the flange 52 and the spring 72
The outer end is urged in a direction to protrude from the outer peripheral surface of the flange 52. An inclined surface 71a is formed at the outer end. A dog 73 is slidably disposed between the locking member 71 and the elastic claw 33. One end 73a of the dog 73 is the plunger 5
It has an inclined surface that engages and disengages from the inclined surface 71a of the locking member 71 when 0 is pressed. Further, the inclined surface of the end portion 73b rides on the elastic claw 33 and can be locked or detached. dog 73
is supported by a bracket 74 so as to be movable in the radial direction (horizontal direction in FIG. 1). The locking member 71 has a hole 71b in which a pin 75 for preventing removal is arranged.

When the plunger 50 is pushed from the return state shown in FIG. 1 to the operating state shown in FIG. The dog 73 engaged at the end 73b is prevented from moving radially inward. At this time, the locking member 71 is locked to the bottom surface of the wall 74a of the bracket 74. Therefore, in the locking member 71, the plunger 50 is connected to the spring 56.
The elasticity prevents it from moving to the return position.

A negative pressure valve 54 is arranged below the plunger 50, and as shown in FIG. 1, the negative pressure valve 54 is in contact with the lower end of the plunger 50 in the return position. The negative pressure valve 54 is a pressure valve mechanism 60
constitutes part of. A flange-shaped valve portion 5 is provided at the lower end of the negative pressure valve 54.
5 is provided.

The valve portion 5 of the plunger 50 is located at the bottom 23 of the housing 20.
5 forms a passage chamber (1).

The pressure valve mechanism 60 including the negative pressure valve 54 and the passage chamber (1) is
Negative pressure valve 54 installed in passage chamber (1) and of negative pressure valve 54
It has a negative pressure spring 66 that urges the plunger 50 in a direction to bring it into contact with the lower end of the plunger 50.

Further, the outer diameter of the valve portion 55 is smaller than the inner diameter of the bottom portion 23, and a passage C is formed. Further, an annular positive pressure valve 61 extending outward from the outer periphery of the negative pressure valve 54 is slidably attached. The positive pressure valve 61 is provided with two lips 61a and 61b that protrude concentrically and annularly toward the valve portion 55. The annular recess formed between the outer lip 61a and the inner lip 61b is connected to the passage chamber (1) through the passage C as a pressure acting part 62. Although not shown in detail.

The interior of housing 20 is open to the atmosphere through various holes or passageways.

Further, the outer lip 61a is located at the shoulder portion 2 on the housing 20 side.
5, and the inner lip 61b is removable from the back surface of the valve portion 55. Inner lip 61b and valve portion 55
The annular recess surrounded by forms a pressure acting part 63.

Between the outer peripheral angle of the negative pressure valve 54 and the inner peripheral surface of the positive pressure valve 61,
A plurality of slits 1c are formed, and the pressure acting portion 63 is exposed to the atmosphere through the slit 61c through the inside of the housing 20.

Further, a retainer 64 is integrally connected above the positive pressure valve 61, and a positive pressure spring 67 is disposed between the retainer 64 and a fixed retainer 65. The identified retainer 65 is fixed to the holding part 26 of the housing 20,
A positive pressure spring 67 urges the positive pressure valve 61 to come into contact with the shoulder portion 25 . The fixed retainer 65 is provided with a through hole 65a through which the negative pressure 54 is inserted, and the slit 61c is opened to the atmosphere through the through hole 65 of the fixed retainer 65 through the inside of the housing 20.

Next, the function of the fuel tank cap according to this embodiment will be explained.

The pressure inside the fuel tank is lower than a predetermined level, and the difference between the atmospheric pressure acting on the pressure acting part 63 and the pressure inside the fuel tank has become larger than the spring elasticity of the negative pressure spring 66 in the passage chamber (1). In this case, as shown in FIG. 2, the negative pressure valve 54 moves downward against the elasticity of the negative pressure spring 66. When the negative pressure valve 54 is separated from the plunger 50, the negative pressure valve 54
The valve portion 55 is separated from the positive pressure valve 61 to create a gap, and air flows from the inside of the fuel tank through the passage chamber (I) and the passage C, and from the passage chamber (■) in the gap via the slit 61c and the through hole 65a. An intake passage is formed that communicates with the housing 20, thereby allowing atmospheric air to flow into the fuel tank.

On the other hand, if the gas pressure in the fuel tank rises above a predetermined level and the difference between the pressure in the fuel tank acting on the pressure acting part 62 and the atmospheric pressure becomes larger than the spring elasticity of the positive pressure spring 67, The positive pressure valve 61 moves upward against the elasticity of the positive pressure spring 67. When the positive pressure valve 61 is separated from the shoulder portion 25.

The lip 61a separates from the shoulder 25 to create a gap, which passes from the inside of the fuel tank through the passage chamber (I) and the passage C, and from the passage chamber (II) in the gap to the slit 61c and the through hole 65a or the lip 61a and the shoulder. An exhaust passage is formed that communicates with the inside of the housing 2o via the gap between the fuel tank and the housing 2o, thereby allowing the gas in the fuel tank to flow out to the atmosphere.

When removing the fuel tank cap from the filler neck, the operator presses the top surface 51 of the plunger 5o, which is in the return position flush with the cover 30, against the elasticity of the spring 56, as shown in FIG. The pressure valve 54 moves downward away from the positive pressure valve 61 against the elasticity of the negative pressure spring 66.

Therefore, similar to the effect of excessive negative pressure, the valve portion 55 is separated from the positive pressure valve 61, and the inside of the fuel tank is filled with a passage chamber (I).
), passage C1 pressure acting part 62, passage chamber (■) due to the created gap, pressure acting part 63. Slit 61c and through hole 6
It communicates with the inside of the housing 20 through 5a and is exposed to the atmosphere.

When the plunger 5o is sufficiently pressed downward from the return position shown in FIG. 1 and reaches the operating position shown in FIG. 2, the latch mechanism 7
0 works. That is, by pushing the plunger 50, the flange 52 moves downward, and the inclined surface 7 of the locking member 71
1a slides on the edge of the wall 74a of the bracket 74, and the spring 72 causes the locking member 71 to protrude from the outer peripheral surface of the flange 52 and lock onto the bottom surface of the wall 74a. . The protruding locking member 71 abuts one end 73a of the dog 73 and prevents the dog 73 from moving radially inward.

The inclined surface of the other end 73b of the dog 73 rides on and engages the elastic claw 33. In this condition, the plunger 5° is held in the operating position shown in FIG. 2, and the pressure within the fuel tank is communicated to the atmosphere, as described above. Therefore, when the pressure within the fuel tank is high, this pressure is released to the atmosphere when the plunger 50 is depressed.

Conversely, when the pressure inside the fuel tank is low, the plunger 50
Atmospheric air flows into the fuel tank when pressed.

Next, when the cover 30 is grasped and rotated in one direction, the elastic claw 33 comes into contact with the vertical surface 22a of the latch 22, and the cover 30 is rotated in one direction.
A rotational torque of 0 is transmitted to the case 10 via the housing 2°. The case 1o is rotated in the direction in which the screw 11 is removed. in this way.

The fuel tank cap is removed from the filler neck to open the fuel filler port.

When the fuel tank cap is screwed into the fuel filler port again after refueling, the plunger 50 is in the operating position shown in FIG. 2. When the cover 30 is rotated in the opposite direction, the torque adjustment mechanism 40 is activated. That is, the elastic claw 33 contacts the inclined surface 22b of the latch 22 and transfers the rotational force of the cover 30 to the case 1.
However, when the rotational force reaches a certain level or higher, the elastic pawl 33 is elastically deformed upward and disconnected from the inclined surface 22b, and a certain rotational torque is applied to the case 10. When the elastic claw 33 climbs over the inclined surface 22b of the latch 22, the upward movement of the elastic claw 33 causes the dog 73 to move radially inward due to the inclined surface of the end 73b of the dog 73, so that the locking member 71 It is pushed into the flange 52 against the elasticity of the spring 72. Therefore, the locking member 71 comes off from the locking end 74a of the bracket 74, and
Plunger 50 is moved by spring 56 from the operating position shown in FIG. 2 to the return position shown in FIG.

The above embodiments of the invention can be modified. 4 to 6 show other embodiments of the invention.

In these drawings, the same parts as those shown in FIGS. 1 to 4 are designated by the same reference numerals, and their explanations will be omitted.

The end surface of the flange 52 of the plunger 50 has a tapered surface 5.
2a is provided. Further, a locking member 75 having an inclined surface 75a that engages with and disengages from the tapered surface 52a is provided so as to be movable in the radial direction. The inclined surface 75a of the locking member 75 is formed with substantially the same inclination angle as the tapered surface 52a. By moving the plunger 50 downward, it is moved radially outward. The locking member 75 is urged by a spring 76 in the direction of contacting the flange 52 . Further, the locking member 75 is provided with an inclined recess 75b, and a dog 77 is provided in the inclined recess 75b.
is removably disposed within the hole 78a of the plate 78.

The dog 77 is supported by a plate 78 so as to be movable substantially perpendicular to the direction of movement of the locking member 75 and substantially parallel to the direction of movement of the plunger 50.

When the plunger 50 in the return position shown in FIG. 4 is pushed downward toward the operating position, the tapered surface 52a of the flange 52 slides along the inclined surface 75a of the locking member 75.
As shown in FIG. 5, the flange 52 is locked to the bottom surface of the locking member 75, and the plunger 50 is held in the operating position. Gas in the fuel tank is released to the outside.

Grip the cover 30 and rotate it in the removal direction.

The dog 77 abuts against the vertical surface 22a of the latch 22.

The rotational torque of the cover 30 is directly transmitted to the case 1o via the housing 20. The case 10 is loosened in the direction in which the screw 11 is removed from the filler neck side, and the fuel tank cap is removed from the filler neck.

When the fuel tank cap is screwed into the fuel filler port after refueling, the dog 77 is engaged with the latch 22 at a position away from the inclined recess 75b of the locking member 75. When the cover 30 is rotated in the opposite direction, the torque adjustment mechanism 40 is activated and the dog 77 overcomes the inclined surface 22b of the latch 22. dog 7
7 presses the inclined recess 75b of the locking member 75.

As a result, the locking member 75 is moved radially outward against the spring 76, and the locking member 75 and the flange 52 are disengaged. Therefore, the plunger 50
6, it is returned to the return position shown in FIG.

Although the above-mentioned embodiment shows an example of a fuel tank cap having a thread 11 formed thereon, it will be understood that the present invention can also be applied to a fuel tank cap that is attached to a filler neck by a locking portion other than a thread.

As explained above, the fuel tank cap according to the present invention reliably forms a passage connecting the inside of the fuel tank to the atmosphere by moving the plunger, so it is easy to remove the fuel tank cap from the filler neck. Before this, it becomes possible to sufficiently release the gases accumulated in the fuel tank into the atmosphere.

Therefore, it is possible to prevent a fire accident when removing the fuel tank cap.

[Brief explanation of drawings]

FIG. 1 is a side cross-sectional view showing a fuel tank cap according to an embodiment of the present invention in an attached state, FIG. 2 is a side cross-sectional view showing a degassing state, FIG. 3 is a plan view, and FIG. FIG. 5 is a side sectional view showing another embodiment, FIG. 5 is a side sectional view showing the degassing state of FIG. 4, and FIG. 6 is a plan view. 10...Case, 12...Opening end, ], 4...Vent, 20...Housing, 21...Opening end, 2
4...Opening, 30...Cover, 33...Elastic claw,
40...torque lubrication mechanism, 5o...plunger,
52...Flange, 54...Negative pressure valve, 55...Valve portion, 56...Spring, 60...Pressure valve mechanism, 61
..Positive pressure valve, 62..Pressure acting part, 65..Retainer, 65a..Through hole, 66..Negative pressure spring. 67...Positive pressure spring, 70...Latch mechanism, 71
・Locking member, 72 ・Spring, 73 ・Dog, 74 ・・Bracket. 74a... Wall, 75... Locking member. Figure Figure 1 Figure 3 Figure 4 3b 3 Figure Reference Figure 5 6

Claims (5)

[Claims] (1) A case having one end formed with an open end, the other end formed with a vent leading into the fuel tank, and an outer periphery formed with a locking part that locks onto the filler neck of the fuel tank; A housing having an opening that communicates with the inside of the fuel tank through a vent hole and fixed within the case, a cover that is rotatably attached to the open end of the case and covers the case and the housing, and the case is screwed into the filler neck. There is a torque adjustment mechanism that disconnects the operational connection between the case and the cover when the rotational torque generated when the cover is rotated in the direction exceeds a predetermined value, and a torque adjustment mechanism that opens the valve when the inside of the fuel tank exceeds a predetermined level. A fuel tank cap equipped with a pressure valve mechanism that releases pressure to the atmosphere, includes a plunger attached to the cover so as to be movable between an outer return position and an inner actuation position, and a plunger that is movably mounted on the cover to move the plunger outward. By moving the plunger from the return position to the operating position against the elasticity of the spring, the pressure valve mechanism is opened and the pressure inside the fuel tank is released to the atmosphere. A unique fuel tank cap. (2) The pressure valve mechanism consists of a positive pressure valve that communicates the pressure inside the fuel tank to the atmosphere when the pressure inside the fuel tank exceeds a predetermined positive pressure level, and a plunger that moves to the operating position or inside the fuel tank. The fuel tank cap according to claim 1, further comprising a negative pressure valve that releases the pressure inside the fuel tank to the atmosphere when the pressure in the fuel tank exceeds a predetermined negative pressure level. (3) The fuel tank cap according to claim (1), further comprising a latch mechanism for holding the plunger in the operating position. (4) When the plunger is in the operating position, the latch mechanism is latched to a part of the torque adjustment mechanism, and when the torque adjustment mechanism is activated, the latching mechanism is released and the plunger is returned to the return position. The fuel tank cap according to claim (1) or (3). (5) The fuel according to claim (1), wherein the negative pressure valve and the positive pressure valve are arranged so as to be in contact with each other, and the pressure in the fuel tank is communicated with the atmosphere by relatively separating the negative pressure valve and the positive pressure valve. Tank cap.